Process of preparing ortho-aminoaldehydes of the anthraquinone series



, tones. 20 mentioned intermediate products are anthra- Patented Nov. 3, 1931 UNITED 'sTATES PATENT 1 orrlcr.v i

11 KARI: WILKE, OF HOCHSTON-THEI-MAIN, GERMANY, ASSIGN OR TO GENERAL ANILINE WORKS, INC., OF'NEW YORK, N. Y., A CORPORATION OF DELAWARE PROCESS OF PREPARING ORTHO-AMINOALDEHYDES OF THE ANTHRAQUI'NONE SERIEs No Drawing. Application filed March a, 1927, Serial 1%. 172,555, and in Gama March a, 1926.

My present invention relates to ortho-aminoaldehydes and ortho-aminolretones of the anthraquinone series.

I have found that ortho-aminoaldehydes A 5 and ortho-aminoketones of the anthraquin- 1'0 thraquinones at a low temperature and which are insoluble in cold alkalies and distinguished bytheir great reactivity (see for instance U. S. Patent No. 1,417,875). The products corresponding to the l-nitro-Q- 1 5 methylanthraquinones are thus converted into the ortho-aminoaldehydes, the products corresponding to the 1--nitro-2-ethylanthraquinones, however, into the ortho-aminoke- This reaction shows that the abovequinoneisoxazoles and proves the correctness of the supposition'as regards their constitu.

tion which could hitherto only be deduced N from the empiric composition determined by 25 analysis. The manner in whlch these prodnets are formed does not indicate a priori that o N- --o b I OH 59 one-2-a1dehyde having the formula; 7

O NH:

ll l

1 part of anthraquinone-1.2-isoxazole (which 1s obtainable for instance by the action of fuming sulfuric acid upon1-nitro-2-methyl anthraquinone) is mixed with 2 parts of l-soe dium hydrosulfite in an aqueous ammoniacal solution and the mixture isheated on the wa ter bath, while excluding air, until the mass is dissolved. By subsequently introducing I (2) Preparation. of 1-amino-2-acetylanthraquinone (1-aminoanthaquinone-2-methylketone) having the formula:

o NH;

I (JO-CH3 manner indicated in example 1, the l-amino- 2-acetylanthraquin0ne is obtained, which, when recrystallized from glacial acetic acid, forms coarse red needles melting at 220 C. It dissolves in an ammoniacal hydrosulfite solution to a reddish-yellow, in a caustic alkaline solution to a brown solution.

(3) A thin paste of anthraquinone-1.2- isoxazole (of. Example 1 of U. S. patent specification No. 1,417,875) to which an excess of sodiumbisulfite solution has been added, is heated to boiling until the yellow color of the isoxazole has disappeared and a red, finely crystalline precipitate is formed, which is filtered by suction, washed and dried. The product is 1-aininoanthraquinone-2-aldehyde and identical with the product obtainable according to Example 1.

(4) 100 parts of 1-nitro-2-1nethylanthraquinone are mixed while stirring at 510 C. with 600 parts of fuming sulfuric acid containing of anhydride, and the melt thus produced is diluted, while cooling, with 900 parts of sulfuric acid of 90% strength. Into the resulting solution of anthraquinone-LQ- isoxazole is run a solution of 210 parts of ferrous sulfate in 500 parts of water, while maintaining the temperature at about 3040 C. The mixture is then poured in water, the precipitating 1-aminoanthraquinOne-Q-aldehyde is filtered and washed first with water, then with a diluted alkali, again with water, and finally dried.

(5) A paste of the 5-nitroanthraquinone- 1.2-isoxazole (obtainable by introducing,

while cooling, 1 part of 1.5-dinitro-2-methylanthraquinone into about 15 parts of fuming sulfuric acid containing 40% of anhydride, and diluting with water), is mixed with an excess of ferrous sulfate and heated to boiling until the yellow color of the isoxazole has disappeared and a reddish-brown precipitate is formed. When dried and recrystallized from chlorobenzene or glacial acetic acid, the precipitate forms a brown crystalline powder whichgives a red mark and melts at 228 C. It dissolves in concentrated sulfuric acid to a pale reddish-yellow solution which, on the addition of formaldehyde, changes to a deep blue. It gives with alkaline hydrosulfite a vat of a spendid green color. Analysis shows that l-amino-S-nitroanthraquinone-Q-aldehyde is formed. The reaction may be represented-as follows:

0 NO NH2 H NO: 0

dehyde is precipitated by means of water, and after addition of a solution of some common salt, filtered,washed and dried. Its yield amounts to about 97% of the theory.

(7) Preparation of 1.5-diaminoanthraquinone-2.6-dialdehyde having the formula:

OI NH:

-on=o 1 part of 1.5-dinitro-2.6-dimethylanthraquinone is introduced, while well cooling, into 15 parts of fuming sulfuric acid containing of anhydride. The resulting 1.2.5.6-diisoxazole is introduced into a dilute solution of sulfuric acid containing an excess of ferrous sulfate and stirred at the temperature of the water bath until the brownishyellow color of the suspended body has changed to a dark red. The reaction product is filtered by suction, washed and dried. It constitutes a red powder, which crystallizes from nitrobenzene in violet-red needles of the melting point 340 C. The color of its solution in concentrated sulfuric acid is brownish yellow, which on addition of formaldehyde changes to blue. It gives with alkaline hydrosulfite a vat of an emerald-green color.

(8) Preparation of 1.8-diaminoanthraquinone-2.7-dialdehyde having the formula:

11TH, NH,

If for the 1.5-dinitro-2.6-dimethylanthraquinone as used in example 7 is substituted the 1.8-dinitro 2.7 dimethylanthraquinone and the further operations are carried out in the manner indicated in this example, there is obtained by way of the anthraquinone- 1.2.8.7-diisoxazole the 1.8-diaminoanthraquinone-2.7-dialdehyde as a bluish-red paste which, after drying, forms a dark-red powder.. The substance crystallizes from nitrobenzene in dark-violet needles dissolving in concentrated sulfuric acid to a brownishyellow solution. The vat prepared therefrom with alkaline hydrosulfite has a green color.

I claim:

1. A process which comprises treating an anthraquinone-a-B-isoxazole compound of the series including anthraquinone-1.2-isoxazole, anthraquinone-1.2.5.6-diisoxazole, anthraquinone-1.2.8.7-diisoxazole, with a reducing agent.

2. A process which comprises reducing an anthraquinone-a-B-isoxazole compound of thraquinne-1.2.8.7 -diis0xazo1e, with ferrous sulfate.

3. Process of preparing l-amino-anthraquinone-SZ-aldehyde having the formula O NH:

which comprises treating anthraquin0ne-12- isoxazole with a reducing agent.

4. Process of preparing l-amino-anthra- 5 quinone-Q-aldehyde having the formula (1 NH: O

which comprises reducing anthraquinone- 1.2-is0xazo1e with ferrous sulfate.

In testimony whereof, I afiix my signature.

KARL WILKE. 

